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In this work, a novel silicone composite with low smoke, high flame retardancy, and good overall mechanical properties was prepared, and the flame-retardant mechanism of sepiolite was explored by studying the application of magnesium hydroxide/melamine/starch/sepiolite system in silicone rubber. The impact of the dosage of sepiolite on the mechanical performances of SR composites was studied. The results showed that when the dosage of sepiolite was 20 phr, the comprehensive mechanical performances of the SR composite were the best. The flame-retardant performances of the specimens were characterized by vertical combustion, the limiting oxygen index, and CCT. With the increase of sepiolite dosage, the limiting oxygen index and vertical combustion of the composites gradually enhanced, the highest peak values of HRR and SPR gradually decreased, and the values of THR and TSP gradually reduced. The SEM pictures of the char residue of CCT showed that the char layer formed by the composites with sepiolite had fewer cracks and a more robust structure. The results of the Shore OO hardness test showed that the addition of sepiolite significantly improved the strength of the char residue. TGA analysis indicated that the thermal stability of silicone rubber with sepiolite was enhanced. [ABSTRACT FROM AUTHOR]

The development of sustainable, efficient and durable flame-retardant (FR) coating for silk fabric using plant-derived phytic acid is of great interest. This work synthesized a novel and reactive intumescent FR agent namely glycidyl phytate isocyanurate (GPIC) through ring-opening addition reaction using phytic acid and 1,3,5-triglycidyl isocyanurate. Then, the durable FR coated silk fabric was developed with GPIC through the surface coating route. The chemical structure of GPIC, and its cross-linking mechanism with silk, the smoke and heat generation performance, flame retardancy and washing durability of coated silk were studied. The coated silk fabric with a weight gain of 13.6 % could self-extinguish and possessed a high limiting oxygen index (LOI) value of 32.5 %. GPIC coating would be covalently cross-linked onto silk fabric and the coated silk fabric could withstand 30 washing cycles, displaying high washing durability. GPIC coating also significantly suppressed the smoke and heat generation of silk fabric during combustion. The coated silk fabrics had high thermal stability and left significant inflated char residues after the burning tests. The intumescent FR performance of GPIC was beneficial from the synergistic effect of phytate and triazine-trione groups. [Display omitted] • Sustainable and reactive glycidyl phytate isocyanurate (GPIC) intumescent flame-retardant is synthesized. • GPIC coating is grafted on silk surface through covalent reaction. • GPIC coating has high flame retardancy and durability on silk textile. • GPIC coating functions by taking advantage of synergistic action of phytate and triazine-trione groups. • GPIC coating offers an eco-friendly and durable flame-retardant approach for silk in practical applications. [ABSTRACT FROM AUTHOR]

Four processing methods were employed to control the localization of intumescent flame-retardant (IFR) and clay in linear low-density polyethylene/nylon 6 (LLDPE/PA6) blends and the effect of IFR and clay localization in blends on flame retardancy was investigated. The results obtained from the LOI and UL-94 tests showed that the flame retardancy in the blends with clay localization in the LLDPE phase was better than that of the blends with clay localization in the PA6 phase. Cone calorimeter test results demonstrated that IFR localization in the PA6 phase caused lower peak heat release rate (PHHR) than in the LLDPE phase. The combined effect resulted in the best flame retardancy exhibited in the blends with localization of IFR in the PA6 phase and clay in the LLDPE phase in comparison with the blends with other localization of IFR and clay. Scanning electron microscopy showed that clay localization in the LLDPE phase and IFR localization in the PA6 phase promoted the formation of an integrated and highly expansive char layer. It is believed the results of the study provide the references for optimizing the flame retardancy of polymer blends. [ABSTRACT FROM AUTHOR]

The extemporaneous combustion of coal remains a major threat to safety in coal mines because such fire accidents result in casualties and significant property loss, as well as serious environmental pollution. This work proposed the fabrication of flame-retardant rigid polyurethane foam (RPUF) containing expandable graphite as char expander/sealant with melamine phosphosphate and 2-carboxyethyl (phenyl)phosphinic acid as char inducer and radical trapping agents. The as-prepared RPUF successfully inhibited coal combustion by forming thermally stable high graphitic content expandable intumescent char sealing over the coal. The RPUF achieved UL-94 V-0 rating in addition to significant reductions in peak heat release, total heat release, and CO and CO2 yields. The external and the internal residual char structure was studied by X-ray photoelectron spectra, Raman spectroscopy, and real-time Fourier transform infrared spectra techniques, and a flame-retardant mode of action has been proposed. This work provides important insight into a facile fabrication of highly efficient and economical flame-retardant RPUF to inhibit the spontaneous combustion of coal.

[Display omitted] • A superhydrophobic, flame-retardant and antibacterial coating is prepared. • Micro/nano-scale protuberances are formed by an in-situ growth process. • The performance improvements come from the arrangements of P/N/Fe elements. • The coated substrate has appreciable durability. To meet the growing demands of multifunctional fabrics in different scenarios that require fire safety, developing flame-retardant coatings with integrated superhydrophobicity and antibacterial properties is imperative. However, how to simultaneously achieve all these features is still a big challenge. Here, a novel multifunctional coating containing polyethyleneimine (PEI), phytic acid (PA), iron ion (Fe3+) and dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (QAS) is constructed by a facile dip-coating strategy. Attributed to the in-situ growth process of the phytic acid metal complex aggregations, the designable hierarchical micro/nano-scale protuberances can be generated. The resultant coating exhibits a good liquid repellency with water contact angles above 155°. Benefiting from the intumescent effect, the coating can produce a dense char layer, and hence to give the coated fabrics a self-extinguishing behavior in the vertical burning test with a limiting oxygen index value of ∼28.5%. Due to the presence of N+ and alkyl chain of QAS, the coating exhibits appreciable antibacterial activity and self-cleaning ability. Additionally, the multifunctional coating can endure more than 20 washing cycles and 100 abrasion cycles without losing its hydrophobicity, flame retardancy and antibacterial properties. The performance and function improvements mainly come from the well arrangements of phosphorus, nitrogen and metal elements. The multifaceted features enable promising applications of such coating in advanced functional textiles, protective clothing, transportation facility, etc. [ABSTRACT FROM AUTHOR]

A char forming agent and silica-gel microencapsulated APP were selected to form novel intumescent flame-retardant system (IFR) to prepare flame-retardant low-density polyethylene (LDPE) composites, and then the influence of zeolites on the thermal and flame-retardant properties of flame-retardant LDPE composites were studied. With the addition of 1 wt% zeolites to LDPE/IFR system, the LOI value increases from 29.0 to 34.0 %. The results of cone calorimetry show that the heat release rate peak and total heat release of the intumescent flame-retardant LDPE composite with 1 wt% zeolites decreases remarkably compared with that of without zeolites. The scanning electron microscopy indicates zeolites with suitable content can improve the quality of the char layer of flame-retardant LDPE composite which is more coherent and dense. The zeolites with the appropriate content can remarkably improve the flame-retardant properties of the LDPE composites. [ABSTRACT FROM AUTHOR]

Abstract: The thermal oxidative degradation kinetics of pure PP and the flame-retarded (FR) PP materials with intumescent flame-retardant (IFR) master batches in situ prepared in twin-screw extruder were investigated using Kissinger method, Flynn–Wall–Ozawa method and Coats–Redfern method. The results showed that the activation energy order of PP and FR PP samples with different blowing agent/char former ratios obtained by Kissinger method agrees well with that obtained by Coats–Redfern one, which well illustrates the relationship between the composition of IFRs and their flame-retardancy, i.e. FR material with richer carbonization agent has higher activation energy for thermal oxidative degradation, hence leading to a better flame-retardancy. For Flynn–Wall–Ozawa method, due to its adoption of Doyle approximation, the obtained activation energy and its order of samples are very different from those of both Kissinger and Coats–Redfern methods. Criado method was finally used to determine the degradation reaction mechanism of various samples. [Copyright &y& Elsevier]

[Display omitted] • A novel environment-friendly and intumescent flame-retardant for coal's spontaneous combustion. • The retardant has good efficiency in both low temperature and high temperature stages of coal's spontaneous combustion. • Systematic analysis of the inhibitory mechanism of this intumescent flame-retardant during spontaneous combustion of coal. The present paper proposes an intumescent flame-retardant, which is suitable for the entire process of spontaneous combustion of coal. Scanning electron microscopy (SEM), simultaneous thermal analysis, in situ FTIR, and temperature programmed experiment were adopted to analyze its inhibiting effect and mechanism. The results indicate that the flame-retardant can play good inhibitory effects during all stages of coal oxidation and decomposition. In the low-temperature stage of 30–120 °C, the flame-retardant carries a lot of water and the surface temperature of coal is reduced since the evaporation of water removes heat. Meanwhile, the hydroxyl groups in the flame-retardant can connect with the -COO- groups on the surface of coal through hydrogen bonds, and enhance the stability of coal. With the temperature increase, some interlamellar water molecules in Mg-Al-CO 3 layered double hydroxides (LDHs) are removed, which reduces the surface temperature of coal. When the temperature is higher than 170 °C, the IFR/LDH undergoes alcholysis and expands, releasing a large amount of non-flammable gas to dilute the oxygen around coal. When the temperature reaches 300 °C, the expanded foam layer is carbonized and forms a porous char layer, thereby inhibiting the combustion. The CO release of coal sample with flame retardant reduces significantly. The temperature with the maximum weight loss rate increases by 50–70 °C, while the heat release reduces by 11.1–24.2%. After calcination at 500 °C for 30 min, the carbon residue is more than 1.6 times that of the untreated coal sample. [ABSTRACT FROM AUTHOR]

• The UV-curable multifunction bio-coating was fabricated based on mussel-inspired chemistry. • A novel flame retardant was successfully synthesized and applied. • A biological adhesive primer has been developed on wood for improved bonding properties. • The the priming mechanism was analyzed by quantum chemistry methods. Using the principles of green chemistry and its technology application, we proposed a robust strategy for fabricating a mussel-inspired transparent, halogen-free, flame retardant and good adhesive coating on the wood surface via a UV-assisted radical polymerization reaction. A novel phosphorus-containing flame retardant diallyl 4-phenylphosphonicbenzoic (DAPB) was successfully synthesized and applied to form the soy oil-based coating resin. The combination of the biocoating with the biological adhesive primer applied on wood offers a green and versatile strategy to replace the toxic and energy-intensive silane-based coupling agents currently in common use. The study shows that the coated wood had a strong self-extinguishing ability and could pass the UL-94 V-0 combustion test. The adhesional energy and the priming mechanism were systematically analyzed by quantum chemistry. From a broader perspective, the processing strategy of priming a surface provides a new platform for material surface UV-cured biocoating and has practical value in widely solving biointerface problems. Besides, the fabricated coating can also be applied to various flammable materials from fire, such as textile and filter paper, cotton surfaces, and extend their innovative applications. [ABSTRACT FROM AUTHOR]

The extemporaneous combustion of coal remains a major threat to safety in coal mines because such fire accidents result in casualties and significant property loss, as well as serious environmental pollution. This work proposed the fabrication of flame-retardant rigid polyurethane foam (RPUF) containing expandable graphite as char expander/sealant with melamine phosphosphate and 2-carboxyethyl (phenyl)phosphinic acid as char inducer and radical trapping agents. The as-prepared RPUF successfully inhibited coal combustion by forming thermally stable high graphitic content expandable intumescent char sealing over the coal. The RPUF achieved UL-94 V-0 rating in addition to significant reductions in peak heat release, total heat release, and CO and CO2 yields. The external and the internal residual char structure was studied by X-ray photoelectron spectra, Raman spectroscopy, and real-time Fourier transform infrared spectra techniques, and a flame-retardant mode of action has been proposed. This work provides important insight into a facile fabrication of highly efficient and economical flame-retardant RPUF to inhibit the spontaneous combustion of coal. [ABSTRACT FROM AUTHOR]